Geoff Levick reckons he's driven from Petone to Palmerston North maybe 50, perhaps 100 times. For more than two decades, Levick ran a business importing chemicals and plastic materials and would make the trip to visit clients. He would drop in to see one client, a factory in Petone, before heading to another in Palmerston North.

The journey always took him between 1 hour, 50 minutes and 1 hour, 55 minutes - normally around lunch time, in light traffic flows. The route is virtually identical to the one the Crown say Mark Lundy drove to kill his wife and daughter - a 300km round trip back to Petone - in two hours and 35 minutes. As well as running 500m from his car to the house, putting on overalls and a wig, finding the murder weapon, tampering with the computer, committing the heinous acts, staging a break-in, running back to the car and disposing of the evidence. All without being seen.

The time frame was "impossible" according to Levick, now retired and living on a farm west of Auckland.

"When they arrested Lundy, I said to my wife, 'they're going to have to stitch him up because you can't do the drive'," Levick told the Weekend Herald.

"The only impression I had was that I was very sceptical of the drive time. Other than that, it was only what I read in the newspaper."

Lundy was convicted of murdering Christine and Amber Lundy in 2002; the Court of Appeal upheld the guilty verdicts and then lifted his minimum jail term to 20 years.

The next year, Levick read a newspaper article about a small group of supporters who believed Lundy was innocent.

Related Content

"They were all close friends or rellies of Lundy, who absolutely assured me that Lundy was a really, really nice guy and he didn't commit these murders."

But why would Levick, a successful businessman heading towards a peaceful retirement, go in to bat for one of New Zealand's most reviled murderers?

"Personally, I don't like being accused of something I haven't done. It gets up my snout. Everybody has a phobia. Mine is being tried, convicted and executed for something I didn't do.

"Once I became convinced the case against Lundy was fundamental nonsense, well, I wasn't going to give up. I'm very bloody stubborn."

From 2004 to 2007, Levick pored over the case. Reading the transcript of the trial over and over again, researching complex forensic science, and uncovering police documents that were never disclosed by police.

After building his case, Levick looked to publicise what he firmly believed was a miscarriage of justice. He met Mike White, an award-winning journalist for North & South, who wrote an 18-page feature in early 2009 examining the Crown case against Lundy.

Much of what was written - including the "brain tissue" evidence, the time of death and the computer tampering allegation - formed the basis of the successful bid to the Privy Council.

The article gave Levick "a bit of a break".

Two barristers contacted him offering to work pro bono to take the case to the Law Lords in London. And Professor Helen Whitwell, a forensic and neuropathologist, offered her expertise to attack the science used to convict Lundy.

But time kept ticking and by the end of 2010, Levick had become frustrated.

The lawyers working for free "still had to pay the bills", says Levick "and this is no criticism of them", so the Privy Council bid had to be fitted around their professional obligations.

So he emailed John McLinden, QC, an expat Kiwi lawyer in London who had provided a legal opinion to Lundy's defence team after the Court of Appeal bid was turned down.

Over the next six months, McLinden and Levick kept in contact until the campaign hit another roadblock. The lawyer's wife became very ill and he had to stop work to take care of her.

"But John McLinden made this huge gesture and said, 'I'll find you someone else'," recalls Levick.

The QC had already been working behind the scenes with Malcolm Birdling, a young New Zealand lawyer completing his PhD at Oxford, which examined wrongful convictions, and approached a fellow expat in London, Dave Hislop, QC.

The trio agreed to meet Levick in London in June 2011.

"I was extraordinarily nervous when I went into the meeting. But within five minutes, I felt completely relaxed that these guys were genuine, intelligent people with a keen interest in the case," said Levick.

"They said, 'Right, Geoff, we will take it on'."

A few months later, Birdling - who had already assisted the late Greg King on the last New Zealand case at the Privy Council, defending John Barlow - flew out to meet Lundy and spent hours reading documents at Levick's home.

The team drafted an 80-page submission asking the Privy Council for leave to appeal, but the Law Lords will accept only 10 pages of submissions. So Birdling managed to cut the draft to 16 pages, for which special permission was granted to be filed late last year.

Levick did not fly to the three-day hearing in June but was with Lundy's sister, Caryl Jones, and her husband Dave on Monday night when the Law Lords publicly announced the decision to overturn his convictions and order a retrial.

That was the "icing on the cake", he told the Herald later that evening.

"I made Mark Lundy a commitment three or four years ago when I said to him that I will get him to the Privy Council. From that perspective, I was happy months ago, because we got there."

The battle to get to the Privy Council had been a long, hard struggle. Levick estimates he has spent 10,000 hours researching the case over the past 10 years, as well as a considerable amount of his own money. He took issue with Judith Collins' comments this week that there was no need for an criminal cases review commission to independently investigate possible miscarriages of justice.

The Justice Minister said New Zealand's criminal justice system has robust safeguards against miscarriages of justice through the appeals process and the royal prerogative of mercy.

"In my opinion, she's missing the point," says Levick.

"An individual facing a wrongful conviction, can't just wake up in the morning and say 'I'll pop this off to the Privy Council'.

"You need helpers, people who will do things for nothing, find experts. It's absolutely impossible to do it yourself from inside prison, it's completely unfair."

Levick says everyone in New Zealand who has managed to be heard at the Privy Council - and there's not many - has had a champion for their cause.

"Someone who has gone on and on and on. You need time and money to up against the total might of the State."

He points out the work of private investigator Tim McKinnel, who has been the driving force behind getting Teina Pora's convictions overturned and is preparing an appeal to the Privy Council. "On one side you've got a guy working tirelessly for no pay, trying to scrape together a case. On the other side, the state with unlimited funds, people, legal minds. If Judith Collins thinks that's fair, she's not on the same planet as me, I'm afraid."

Now 67, Levick has spent the last 10 years of his life fighting to clear another man's name.

Despite the success in the Privy Council this week, he concedes there is still a strong public sentiment against Lundy. A slob who slept with a prostitute. A husband and father perceived to have "put on a performance" of faux grief at their funeral, hidden behind dark glasses, replayed endlessly on television.

The final word should go to the Privy Council, the second to last paragraph of its 50-page judgment.

"The divisions between the experts are so profound, they range over so many areas and they relate to matters which are so central to the guilt or innocence of the appellant, that the Board has concluded that they may only properly be resolved by the triers of fact in a trial."

Man on a mission

2000: Christine and Amber Lundy murdered in their Palmerston North home.

2002: Mark Lundy convicted and Court of Appeal bid dismissed. Sentenced to 20 years in prison.

2003: Geoff Levick meets a small group of supporters who believe Lundy is innocent.

2004-2007: Levick spends thousands of hours researching the case.

2009: North & South magazine publishes 18-page spread on the new evidence.

2010: Levick approaches John McLinden, QC in London to take appeal to Privy Council.

2011: McLinden introduces Levick to Dave Hislop, QC and Malcolm Birdling who take on the case

2012: Appeal filed to the Law Lords.

2013: Three day appeal heard in London. Privy Council overturn convictions and order a re-trial. Released on bail yesterday.